This invention relates generally to gas turbine engines, and more particularly, to adaptive inertial particle separators and methods of use.
Sand and dust ingestion in gas turbine engines may adversely affect engine performance and reliability, and may also increase the frequency of repair and maintenance required for the engines. Because flight readiness depends at least partially on reliably and properly functioning engines, reducing the occurrence of, and/or the effects of, sand and dust ingestion should facilitate enhancing the reliability of the engines.
Various methods are employed to facilitate reducing sand and dust concentrations channeled via the inlet airflow to the engine compressor. For example, known inertial particle separator (IPS) systems perform well in any weather conditions, are highly reliable, are integrated into the engine, but may not provide adequate separation efficiency during severe sand and dust conditions. Inertial inlet particle separators work by imparting momentum and trajectory on sand and dust particles to channel such particles away from the fluid stream entering the gas turbine engine. The particles removed are then collected or scavenged into an overboard dump. However, the same features that facilitate the separation of sand and dust particles from the inlet air, also cause inlet pressure losses that may detrimentally effect gas turbine engine performance. Because of the permanent nature of known IPS systems, engine performance loss is incurred in clean air and sandy air conditions.
During operation, fluid flow into a gas turbine engine inlet is channeled downstream towards an entry channel. Downstream from a convex section, fluid flow is divided into two fluid streams. One of the streams, known as a dirty fluid flow, is channeled towards a dirty fluid channel. Debris, such as birds, and particles of debris, such as snow and/or ice particles, flow through the dirty fluid channel and into the IPS scavenge system wherein the debris is ejected from gas turbine engine. The other fluid stream, known as a clean fluid flow, is channeled into a clean fluid channel. To facilitate “clean” flow into the clean fluid channel, the clean fluid flow is forced to make a sharp turn around a convex section. Most debris will not be capable of changing direction at the turn, due to the greater inertia and momentum of the debris particles. Consequently, most debris will be channeled into the dirty fluid channel, thus facilitating a flow of clean fluid into the gas turbine engine. IPS systems of this type facilitate removal of large sand particles and debris, but generally such IPS systems are not as effective in removing smaller particles or debris.
Some known helicopters are fitted with bulky barrier filters to address severe sand conditions. Although such filters satisfactorily remove sand and dust from the air, known filters are heavy, detrimentally effect engine performance, require increased maintenance, and are unable to operate in icing conditions. Moreover, known filters also cause a pressure drop at the inlet of the gas turbine engine that also adversely affects engine performance. Furthermore, known filters may also be susceptible to plugging with sand and dust.